﻿// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.ComponentModel;
using System.ComponentModel.Design;
using System.Reflection;

namespace System.Windows.Forms.Design;

public partial class DocumentDesigner
{
    /// <summary>
    ///  Document designer's version of the inheritance service.  For UI
    ///  components, we will allow private controls if those controls are
    ///  children of our document, since they will be visible.
    /// </summary>
    private class DocumentInheritanceService : InheritanceService
    {
        private readonly DocumentDesigner _designer;

        /// <summary>
        ///  Creates a new document inheritance service.
        /// </summary>
        public DocumentInheritanceService(DocumentDesigner designer) => _designer = designer;

        /// <summary>
        ///  <para>Indicates the inherited members to ignore.</para>
        /// </summary>
        protected override bool IgnoreInheritedMember(MemberInfo member, IComponent? component)
        {
            FieldInfo? field = member as FieldInfo;
            MethodInfo? method = member as MethodInfo;

            // We allow private members if they are controls on our design surface or
            // derive from Menu.
            bool privateMember;
            Type memberType;
            if (field is not null)
            {
                privateMember = field.IsPrivate || field.IsAssembly;
                memberType = field.FieldType;
            }
            else if (method is not null)
            {
                privateMember = method.IsPrivate || method.IsAssembly;
                memberType = method.ReturnType;
            }
            else
            {
                Debug.Fail("Unknown member type passed to IgnoreInheritedMember");
                return true;
            }

            if (privateMember)
            {
                if (typeof(Control).IsAssignableFrom(memberType))
                {
                    // See if this member is a child of our document...
                    //
                    Control? child = null;
                    if (field is not null)
                    {
                        child = (Control?)field.GetValue(component);
                    }
                    else if (method is not null)
                    {
                        child = (Control?)method.Invoke(component, parameters: null);
                    }

                    Control parent = _designer.Control;

                    while (child is not null && child != parent)
                    {
                        child = child.Parent;
                    }

                    // If it is a child of our designer, we don't want to ignore this member.
                    if (child is not null)
                    {
                        return false;
                    }
                }
            }

            return base.IgnoreInheritedMember(member, component);
        }
    }
}
